During the last 30 years, numerous reports have confirmed the detrimental effects of cigarette smoking during pregnancy on the health of the fetus, the newborn infant, and the mother. The 1979 Surgeon General's Report identified smoking cessation intervention research as an area of considerable need for rigorous study. While several reports in the literature are available, little insight is available on the effectiveness and durability of smoking cessation interventions for pregant women during pregnancy and up to one year post-delivery. The purpose of this trial is to develop a multi-component smoking cessation intervention and to determine its impact on the cessation and reduction rated during pregnancy at delivery, 6 weeks, 6 months, and 12 months post-delivery. A prospective, randomized, pretest-posttest control group design will be used to evaluate intervention effectiveness among a group of 800 pregnant smokers: 400 women randomly assigned to receive the intervention and 400 randomly assigned to a control group. Behavioral reports, saliva thiocyanate and cotinine samples will be collected at baseline, mid-pregnancy, end of pregnancy, six-weeks post-delivery, six-months post-delivery, and 12-months post-delivery to document behavior change. This trial will apply a three-component intervention program consisting of a self-help smoking cessation guide and skills training, to enhance cessation (Component 1). Systematic reinforcement by chart reminder form (Component 2) and encouragement and systematic application of social support (Component 3) will also be applied. This trial will adapt and revise existing methods found successful in motivating pregant smokers in maternity clinics to quit smoking or to reduce cigarette consumption. The results of this study will provide an insight not currently available about the effectiveness and durability of smoking cessation interventions in maternity clinics during the pregnancy and for one full year post-delivery.